Machine tool



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' ATTORNEYS MACHINE ToorJ Filed May 22, 1947 Patented Apr. 6, 1948-V OFFICE MACHINE 'rooL Frederick E. Munschauer, Buffalo, N. Y., assigner to Niagara. N. Y.

Machine as Tool Works, Buffalo.

Original application June 1, 1945, Serial No. 597,137. Divided and this application May 22, 1947, Serial No. 749,697

'I'hisinvention relates to reciprocating work tablesfor machine tools and the like and particularly to fluid operated tables for machines of this class. This application is a division of my co-pending application, Serial No. 597,137, filed June 1, 194.5.V

Heretofore in this art definite length llimitations have existed which prevented satisfactory fluid operation of reciprocating work tables beyond certain stroke lengths, other factors considered. These limitations arise as av result of natural lateral fiexural deflection of the parts when unusually long cylinders and pistons or piston rods are employed, defiections suliicient in degree to militate against satisfactory operation of hydraulic piston and cylinder constructions which by their nature must have accurate fluidtight engagement, not only as between the pistons and 'cylinders but also as between the piston rods and the cylinder heads.

The present invention provides means whereby sturdy, accurate and wholly satisfactory hydraulic operation may be employed at strokeit is to be understood that the underlying principles are not limited thereto or otherwise `than as defined in the appended claims. In the ensuing description, reference will be had to a surface grinder as one specic example of a machine tool 4 Claims. (Cl. S15-233) remainder being conventional and subject to a wide range of variation in design and arrangement. y

The upper surface of bed I0 is formed with ways I2 and I3 and the under side of table or carriage II has complementary formations for longitudinal movement along the ways I2 and I3.

The table II may have longitudinal side flanges I4 and I5 which extend into further guiding engagement with the longitudinal sides of bed I0.

Both the upper surface of bed II) and the under side of table II have longitudinally extending well formations, designated I6 and .I'l, respectively, Which \cooperate to` accommodate the instrumentalities comprising the hydraulic drive means.

For clearness, Fig. 1 shows only the piston and cylinder arrangement which is closest( to the wherein the principles of the present invention may be advantageously employed.

In the drawings: Fig. l is a longitudinal cross sectionalview of one form of the apparatus of the present invention taken on line I--I of Fig. 2; and

Fig. 2 is a transverse cross sectional view on the line II-II of Fig. 1.

Referring to the embodiment of the invention illustrated in Figs. 1 and 2, the numeral I0 designates a machine bed or base anda reciprocating work table or carriage is designated II. Only so longitudinally in Fig. 1, excepting that it will be reversed end for end. This general reverse duplicate arrangement is well understood by those skilled n the art and no4 useful purpose would be served by duplicate illustrations or further` explanation.

Referring to Fig. 1, a piston 20 has one end fixed securely with respect to bed I0 at one end thereof by means of a bracket 2| and another piston 22 has its opposite end fixed securely to the opposite end of table II as by means of a bracket 23. The free ends of both of the pistons 2n and 22extend into opposite ends of a cylinder 25 and the opposite ends of the latter have suitably packed heads 26 and 21 foruid tight sliding engagement with the pistons 20 and 22.

Cylinder 25 is mounted on bed I 0 in well I6 for longitudinally guided sliding movement and for that purpose is provided with a laterally flanged vbase portion 30 which fits in a longitudinal groove 3| formed inthe base III. A similar but oppositely, operating cylinder is designated 35 in Fig. 2 and' its-flanged base, designated 36, fits in a companion groove 31. Retaining rails for the flanged base portions 30 and 3G are designated 38, 39, and 48 in Fig. 2. v

Cylinder 25 is provided, substantially midway `along its length, with a trunnion 42 which supoperation of the pinion 43 constrains the cylin-l der 25 to movement at one-half the rate of movement of table il and pistons 20 and 22 will move relatively inwardlyand outwardly of cylinder 25 in duplicate manner. With the construction described the two pistons 20 and 22 are about onehalf the length that would be required if a single conventional piston were employed, and, what is more important, the free length of each piston, considered as a structural columri, is only half of lwhat it would be in the case of a single long pistn.

' The other cylinder 35 is provided with a similar but oppositely arranged pinion and rack mechative to said bed and movable axially in said cylinder, other piston meansilxed relative to said work table and movable axially in said cylinder, whereby fluid pressure in said cylinder between said piston means moves the latterrelatively apart, a pinion carried by said cylinder for free rotation, a rack fixed to said bed and meshing with said pinion, and a second rack fixed to said work table and meshing with said pinion at its opposite side, whereby said cylinder automatically moves along said bed at one-half the rate of movement of the work table.

l3. In la machine tool, a bed, a work table mounted for reciprocation thereon, and a pair of opposed drive means for effecting alternate lineal movement thereof in opposite directions, each of said drive means comprising a cylinder guided for longitudinal movement in the direc.- tion of its axis and parallel to the path d movement of said work table, piston means xed relative to said bed and movable axially in said cylinder, other piston means fixed relative to said work table and movable axially in said cylinder,

- whereby fluid pressure in said cylinder between nisxn which is merely designated generally 50 in Fig. 2 and need not be further described.

What is claimed is: l. In amachine tool, a bed, a work table Vmounted for guided linealmovement thereon, and

drive means for eiieting lineal movement thereof, said drive means comprising a cylinder guided for longitudinal movement in the direction of its axis and parallel to thegpath oi movement of,

said Work table, piston means fixed relative to said bed and movable axially in said cylinder,

1 other piston means fixed relative to said Worky table and movable axially in said cylinder,

` whereby fluid pressure in said cylinder between Agear means at its opposite side, whereby said cylinder automatically moves along said bed at a rate bearing a xed fractional relation to the rate of movement of the Wo`rk ltable.

2. In a machine tool, a bed, a work table mounted for guided lineal movement thereon,

said piston means inoves the latter relatively apart, gear means carried-by said cylinder for free rotation, a rack iixed to said bed and meshing with said gear means, and a second rack fixed to said work table and meshing with said gear means at its opposite side, whereby said cylinder vautomatically moves along said bed at a rate bearing a fixed fractional relation to the rate of A movement of the work table.

and drive. means for effecting lineal movement 4.4In a machine tool, a bed, a work table mounted Ifor reciprocation'thereon. and a pair of opposed drive means for effecting alternate lineal' movement thereof in opposite directions,

each of said drive means comprising a lcylinder guided for longitudinal movement in the direction ofits axis/and parallel to the path of movement of said work table, piston means fixed relative to said bed and movable axially in said cylinder, other piston means xed relative to said work table and movable axially in said cylinder, whereby fluid pressure in said cylinder between said piston means moves the latter relatively apart, a rotatable pinion carried by said cylinder for free rotation, a rack fixed to said bed and meshing'with said'pinion, and 'a second rack fixed to said work table and meshing with said pinion at its opposite side, whereby said cylinder automatically moves along said bed at one-half the rate of movement of the work table.

FREDERICK E.' MUNSCHAUER, 

